Built by Adam de Hereford according to historical accounts, this earthwork monument sits on a gentle west-facing slope that has been significantly altered by the modern golf course surrounding it. The main feature is a D-shaped mound measuring 45 metres east to west, with its eastern side forming a straight edge 27 metres long. The height varies considerably; three metres at the eastern end tapering down to just one metre at the western side.

The defensive architecture of this Norman fortification reveals sophisticated medieval engineering. A broad fosse, or defensive ditch, measuring five metres wide and up to one metre deep, curves around the mound from southeast through west to northeast. Beyond this inner ditch runs a substantial outer bank, five metres wide and two metres high, with a second, shallower fosse on its far side. Interestingly, these defensive features don’t extend along the straight eastern edge, though a shallow channel runs northeast from the mound’s base to connect with a nearby stream, possibly serving as a water supply or additional defence. A gap in the western bank appears to have been an entrance, though no corresponding causeways cross the ditches at this point.

Today, the monument has been thoroughly integrated into the golf course landscape, with the 10th green occupying what archaeologists identified as a possible bailey; a lower, square area immediately east of the motte that would have housed the castle’s support buildings and garrison. The motte itself is now squeezed between the 13th green to the north and 12th green to the south, whilst the 11th tee sits just south of the bailey area. Despite these modern intrusions, the site retains its essential character as part of a larger medieval earthwork complex, having been registered as a Historic Monument in July 1976. The surrounding area once featured additional low earthworks and enclosures, testament to what was clearly an important Norman stronghold in medieval Kildare.